I need to stay in the sub-$400 range used. I want detail without harshness, a deeper sound stage and better midrange clarity. Will the Arcam give me that over the Cambridge? If not, then what will given my budget?

Hearing is believing. Take your player to an Arcam dealer and do your own comparison. Listen to a short passages of music you are familiar with closely and repeatitively with your Cambridge, then quickly switch to the Arcam. Do this several times with different music. Good vocal tracks will be the most revealing (I like Diana Krall for this). You will then quite likely be a big believer. Although I am not familiar with the Cambridge, the Arcam is a great player for the money.

I would stick with the Cam. I have listened to both.I was impressed with the Cam,the cd 72 did not do it for me even though it had the Arcam name hooked up to it.I have a cd92 much better sound than the 72 or the Cam.I dont think you will notice enough of a difference to make it worth while.